This year, the weather has stayed in the 80s at the beginning of September, giving drivers a false sense of summer lingering on. Even with sunny skies and dry roads, the Colorado Department of Transportation (CDOT) enforces chain and traction laws starting September 1st through May 31st on Interstate 70 between Morrison and Dotsero. That means whether you’re driving through Vail, Avon, or Eagle, the law applies—regardless of whether there’s snow on the ground.
Understanding these laws is crucial to avoiding fines, keeping the roads safe, and ensuring you’re not left stranded when the weather changes suddenly, which is common in the high country.
The Traction Law (Code 15) requires that all vehicles traveling on I-70 in the mountains during enforcement season (September 1–May 31) meet specific traction requirements. These include:
This law is proactive—it ensures that even when the weather shifts unexpectedly, vehicles have the grip they need to avoid spinouts, crashes, and major traffic backups.
The Chain Law (Code 16) is stricter and usually comes into play during heavy snowstorms. For passenger vehicles, it requires:
For commercial vehicles over 26,000 pounds (like semis and buses), the chain law is even more specific, requiring chains on multiple drive axles.
It may feel odd to think about snow tires and chains when the weather is still mild. But Colorado weather is famously unpredictable. A sunny 70-degree afternoon in Vail can turn into a snow squall over Vail Pass in just a few hours.
That’s why CDOT enforces the law seasonally, not just during active storms. By requiring readiness from September through May, drivers can’t claim “surprise” when the first snowstorm hits. It also prevents dangerous situations where unprepared vehicles cause closures or accidents on steep grades like the Eisenhower Tunnel or Vail Pass.
Failing to comply with traction and chain laws comes with steep consequences:
These fines are costly, but the real danger is being stranded in the mountains—or worse, causing an accident that endangers others.
Even in September, drivers should prepare for the long enforcement season ahead. Here’s a checklist:
Despite good planning, vehicles can still experience breakdowns or get stuck. Colorado weather can turn quickly, and a snowstorm may arrive anytime from September onward. When drivers are caught off guard, towing companies like West Vail Towing & Recovery step in to keep people safe and restore traffic flow on I-70.
West Vail Towing provides:
Even if it’s warm and sunny in September, Colorado’s chain and traction law is in full effect. These requirements are about being prepared ahead of time, not just responding when snow starts to fall. By keeping your vehicle compliant, you avoid fines, protect yourself and others, and help keep Colorado’s mountain highways safe and open.
If you do find yourself in trouble—whether it’s a spinout, breakdown, or accident—West Vail Towing & Recovery is here to help 24/7. Call 970-476-3394 anytime for professional, reliable assistance.